Windows 10 Upgrade Advisor

Windows 10 for mobile phones are now ready and can be installed by using the Windows 10 Upgrade Advisor app which you can download to your Windows 8.1 smartphone from app market.
To upgrade to Windows 10, first download Windows 10 Upgrade Advisor then launch the application.
First enable the app to check if your phone is ready for upgrade.

Then make sure that you have installed all Windows updates before you proceed with Windows 10 Upgrade.
Otherwise you will have to run the Upgrade Advisor app numerous times which makes you to install the updates from Settings app before proceeding with Windows 10 upgrade for your mobile phone.

Unfortunately Nokia Lumia 920 which was the flagship of Nokia Windows Phones is not in the list of smartphones for Windows 10 upgrade list right now.
But there is an announcement from Lumia informing that all Lumia models will be upgraded to Windows 10 mobile edition.
If your Windows Phone is not on the list, we will wait for its turn to come.

Step by Step Windows 10 Upgrade

This guide shows how to upgrade Windows Phone 8.1 smartphone to Windows 10 step-by-step using the Windows 10 Upgrade Advisor.

Here are screenshots taken on my Microsoft Phone from Windows 10 Upgrade Advisor app for upgrading to Windows 10 from Windows Phone 8.1

Download Windows 10 Upgrade Advisor app from marketplace and run it for the first time.

Windows 10 Upgrade Advisor app guides you and provides information about upgrading your smartphone to Windows 10 and helps you to prepare your phone for installing the Windows 10 upgrade.

The app also checks at first hand whether Windows 10 upgrade is available for your phone according to mobile phone brand and model and considering your country.

To see if there is a Windows 10 upgrade for your phone continue with Next button.

Windows 10 Upgrade Advisor is checking for updates on your phone.

If an upgrade is available for your phone, mark the Enable Windows 10 upgrade checkbox and click Next button to continue upgrading to Windows 10 on your Windows Phone.

An other check wil be processed before Windows 10 upgrade is installed for missing patches and available space on your phone.
After this point, I suggest to check if there is a system update on your phone by using the default Settings app for software updates.
Before proceeding with Windows 10 Upgrade, install all software updates to your current Windows Phone 8.1 mobile phone.

Good news that I have enough space for installing Windows 10 on my Microsoft phone.After this point, install all missing Phone updates from Settings app and let the Windows 10 Upgrade Advisor to guide you for the installation.

Check if your Microsoft or Nokia phone is enabled for the Windows 10 upgrade using the Windows 10 Upgrade Advisor tool.